Interpretation of integrated monitoring data gathered at the Lheebroekerzand in the Netherlands

This report describes the handling of the data and the results of the trend- and correlation-analysis.The first objective is to detect and estimate trends in the extensive amount of monitoring data of the chemical, physical and biological variables through time. The second objective is to determine whether correlations between biological and chemical monitoring data are present. Only biological variables showing a trend through time, and chemical variables related to the environmental themes acidification, eutrophication, desiccation and the presence of heavy metals are examined.Results of the trend analysis of the biological variables show that there is no indication for a degradation of the bird, leafminer, epiphyte or macrofauna communities in the Lheebroekerzand. However the decrease in the total number of observed butterflies can be marked as an alarming situation.

The condition of the trees is improving through time. The chemical concentrations of most pollutants indicate a downward trend in the different compartments of the ecosystem, with exception of ammonium, nitrate and sulphate in lakewater, the acidity of the lakewater and the concentration of lead in leaves and needles. Correlations between biological and chemical variables are seen for the presence of butterflies with cadmium, lead and sulphur content in air and deposition. Defoliation of the trees is correlated with sulphur, nitrogen and acidity in air and deposition. Substances responsible for acidification, eutrophication, desiccation and the presence of heavy metals in the ecosystem do not have a marked influence on the presence of birds, leafminers, epiphytes and macrofauna in the Lheebroekerzand.